FIGURES 10–14 in Three new species of the diatom genus Halamphora (Bacillariophyta) from the prairie pothole lakes region of North Dakota, USA

FIGURES 10–14: SEM Halamphora pratensis sp. nov. Fig. 10. External whole valve view. Fig. 11. Internal whole valve view. Fig. 12. Detail of valve apex showing marginal ridge wrapping around distal raphe end to the ventral margin (arrow). Fig. 13. Detail of internal valve center showing thickened central virgae (arrow). Fig. 14. Whole frustule in dorsal girdle view showing girdle bands with two rows of poroids. Scale bars = 1 μm.